Had a pair of 780's and went through 2x pairs of 788's (Both replacements).
The bass was really not great - but I do have a fairly high standard when it comes to audio quality.
In regards to the build quality - the 780/788 is overall good but that design flaw with the headband snapping will happen. No matter how careful you are, the plastic is just too brittle and strained in the spot above the rotational joint.
Perhaps I've just got a large head!!
You can't possibly be using them daily, or you've got a head the size of kitten. They'd of snapped by now.
Either way though, the HyperX Clouds are a much better buy for another fiver.